The invention relates to a tomograph for the production of transverse layer images of a radiography subject, comprising an x-ray measuring arrangement which contains two x-ray sources of different radiation energy which generate radiation beams penetrating the radiography subject, the cross-sectional extent of said radiation beams perpendicular to the layer plane being substantially equal to the layer thickness, and also containing a radiation receiver which determines the radiation intensity behind the subject, as well as comprising a rotating device for irradiation of the radiography subject from different directions, and comprising a computer for the determination of the attenuation coefficients of every image point in an image point-matrix disposed in the examined layer, wherein the computer is so designed that it determines, for every image point, the attenuation coefficient for every radiation energy, and determines therefrom the median ordinate value and the density.
A computer tomograph of this type is known in which, for scanning of the subject, there is present, for every radiation source, one radiation receiver which is fixedly connected with the respective radiation source (U.S. Pat. No. 3,971,948). For scanning of the subject, there alternately takes place a common lateral displacement of both radiation sources and both radiation receivers and a rotation of these structural units. In the case of the known tomograph, it is disadvantageous that the technical outlay for the scanning of the radiography subject is very great.